XENON1T solar axion and the Higgs boson emerging from the dark

TL;DR

This paper proposes a new dark matter production mechanism linking the Higgs boson and a light pseudo-scalar, explaining the XENON1T excess and predicting observable signals like gravitational waves and exotic decays.

Contribution

It introduces a composite dark sector model where a light pseudo-scalar explains the XENON1T excess and predicts testable phenomena in future experiments.

Findings

Pseudo-scalar produced in the sun explains XENON1T excess.

Dark Matter candidate has a mass around 50 TeV, beyond current detection.

Predicted gravitational waves and exotic decays are within future experimental reach.

Abstract

In a recent letter we proposed a new non-thermal mechanism of Dark Matter production based on vacuum misalignment, where both the Higgs boson and a very light pseudo-scalar $\eta$ emerge from the Dark sector. In this letter, we identify the parameter space in a composite scenario where the light pseudo-scalar can be produced in the sun and explain the XENON1T excess in electron recoil data. The model's Dark Matter candidate has a mass around $50$ TeV and out of range for Direct Detection. Testable predictions include Gravitational waves at frequencies in the Hz range from a cosmological phase transition, an exotic decay $Z \to \gamma + \mbox{inv.}$ with rates $4 \div 16 \cdot 10^{-12}$ testable at a future Tera-Z collider, and an enhancement by $17\div 40$ % of the branching ratio $K_L \to \pi^0 + \mbox{inv.}$, not enough to explain the KOTO anomaly. All these predictions may be confirmed by future experiments.